| Summary: | Glacier Peak is a 3,214 m (10,544 ft.) stratovolcano composed mainly of dacite. The volcano is located in the Glacier Peak Wilderness Area, in the Mt. Baker-Snoqualmie National Forest, about 100 km (65 mi) northeast of Seattle and 110 km (70 mi) south of the International Boundary with Canada. Since the continental ice sheets receded from the region approximately 15,000 years ago, Glacier Peak has erupted repeatedly during at least six episodes. Two of these eruptions were among the largest in the Cascades during this time period. This DEM (digital elevation model) of Glacier Peak is the product of high-precision airborne lidar (Light Detection and Ranging) surveys performed during August-November, 2014 and June, 2015 by Quantum Spatial under contract with the USGS. This digital map, totaling approximately 475 square miles, represents the ground surface beneath forest cover and contributes to natural hazard monitoring efforts, the study of regional geology, volcanic landforms, and landscape modification during and after future volcanic eruptions, both at Glacier Peak or elsewhere globally. This release is comprised of a DEM dataset accompanied by a hillshade raster, each divided into 18 tiles. Each tile’s bounding rectangle is identical to the extent of the USGS 7.5 minute topographic quadrangles covering the same area. The names of the DEM tiles are eleven characters long (e.g., dem_xxxxxx). The prefix, "dem", indicates the file is a DEM and the last seven characters correspond to the map reference code of the quadrangle defining the tile's spatial extent. Hillshade tile names are denoted by the prefix "hs", but are otherwise identical to the DEM they are derived from.
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